My father just got a Mac Mini (first mac) and is using it connected to a TV through HDMI.

The problem is that we canīt control the sound neither on the desktop icon (its grayed out) nor with the keyboard (apple wireless keyboard).
We can control the sound just fine with a TV remote control, so the problem isnīt on the TV itself and we can also change the volume on iTunes.

The "old fashioned" analog output would equate to "line out" on a pre-amp and you would increase the volume on the pre-amp (mac mini) which would increase the voltage to the amplifier and thus increase the volume of sound coming from the speakers.

With a digital audio signal (HDMI or audio optical fiber O/P) there may not be a signaling capability for volume so the mini "blanks out" those controls as you observed. I have the same experience but I never took the time to research it. Just used the volume control on the TV or the receiver.

bumping this old thread, trying to control the entire system sound and not just individual players(itunes, vlc), I tired sound source, but that doesnt work either. Any workarounds?

Thanks

As far as I'm aware there are no work arounds. I also have my Mini connected via HDMI and cannot control the system sound directly on the Mini. The only way I can do it is through my surround sound receiver as my Mini is connected to it with HDMI.

The 2011 Mac Mini volume control works under Windows 7 x64 in bootcamp. However, the volume is extremely low. Fortunately, my Sony XBR has individual input volume compensation. Sadly, the Samsung does not. I'd be interested to know if there is a way to boost the sound level as well.

The HDMI port outputs a digital signal (for both video and audio), just like the optical audio output mini-jack. Like fa8363 above stated, HDMI has its audio output level fixed. Meaning that Mac OS X Core Audio simply outputs the sound that it receives from whatever application is sending the signal, and does not change its level. This is the same way a Blu-ray/DVD player/AV receiver outputs HDMI audio signals.

It is possible to change the audio level on the source application e.g. iTunes, VLC, etc but not from the system volume control which is run by Mac OS X Core Audio, when outputting a digital audio signal (HDMI, Thunderbolt, miniDisplayport or optical audio output). That is the reason system volume control is inaccessible when a digital audio signal is output.

If you want to use system volume control then you can connect the analog audio output mini-jack to your display, then go to system preferences>sound>output and select the headphone port for sound output, instead of the HDMI port.

The HDMI port outputs a digital signal (for both video and audio), just like the optical audio output mini-jack. Like fa8363 above stated, HDMI has its audio output level fixed. Meaning that Mac OS X Core Audio simply outputs the sound that it receives from whatever application is sending the signal, and does not change its level. This is the same way a Blu-ray/DVD player/AV receiver outputs HDMI audio signals.

Brilliant explanation, it so common for iOS/Mac: "oh it's just impossible to implement".

But how, I wonder, a particular application controls the volume of output signal, eh? If it is "just a digital stream" there is no chance to control output volume, how do they control it's own sounds? The answer is absolutely the same way as the audio driver could.

It might be implemented absolutely the same way as any particular app controls it's output volume, so the whole system driver could control the volume of total output stream as well. The proofs of this statement are in the other OS like Linux and Windows. You actually CAN control the whole system output volume on HDMI programmaticaly in these OS.

So, the conclusion is: it is the Mac OS X restriction to control the output volume level on digital outputs.

My monitor has 2 HDMI inputs and it has an analog audio output, so I plug my speakers into that output and my mac mini into HDMI 1 and my PC into HDMI 2. When I switch inputs on the monitor, it switches the audio for me also. The monitor does not have any audio inputs besides HDMI, so it cannot switch audio for me unless I use HDMI audio.

I am having the same problem as everyone else with my mac mini. If I plug my speakers directly into the analog line out on the mac mini, I can control the volume with the volume keys on the keyboard, but if I send the audio out through the HDMI, the volume keys don't change the volume, and I can't even change the volume using the volume control in the banner at the top of the screen.

I know that HDMI isn't causing the problem because I am able to change the volume on my PC using the keyboard buttons when I send the PC audio through HDMI. It is clear that when using the HDMI output you can't change the volume on the mac mini, but that is just because that is how Apple implemented it.

I wonder if there is some kind of setting that could fix this, or if Apple could update the software to make it work.

This may not work as seamless on the Mac Mini. I have the same problems as described above, but I'm using a Macbook Pro. So, this may not work exactly as above.

This is currently a free solution (as of Sep, 2012), and it has worked nicely for me. I downloaded and installed an app called Soundflower. Soundflower allows you to change the sound output source. Now, I can be connected to my HDMI TV and control my sound with the built in sound controls.

This may not work as seamless on the Mac Mini. I have the same problems as described above, but I'm using a Macbook Pro. So, this may not work exactly as above.

This is currently a free solution (as of Sep, 2012), and it has worked nicely for me. I downloaded and installed an app called Soundflower. Soundflower allows you to change the sound output source. Now, I can be connected to my HDMI TV and control my sound with the built in sound controls.

I also use HDMI to a Samsung TV/Monitor and have this problem on my mid-2011 base model Mac Mini of not being able to control the software sound controls that are greyed out in OS X Mountain Lion. I have to use the Samsung TV/Monitor remote or TV buttons on the monitor to control the sound level. I know that there are a number of restrictions that audio/video and computer manufacturers have to implement by default in their devices that use HDMI output. I like what I am reading so far about this solution to use Soundflower.

What everyone needs to understand is that it isn't an "issue".... HDMI is a line level audio output. It is designed so that the same "volume" is given whether you plug it into your TV or your receiver and that the audio device (again your tv or receiver) controls the volume. What applications like Soundflower and VLC do is artificially raise or lower the volume using software. Frankly, I think you should control volume with the device that outputs the volume and not the device that just sends the audio signals. Even devices that have their own volume, I usually set to about 75% and let my TV's and or Receivers do all the volume control. In the end they (tv's and receivers) are usually better at volume control than any software hack.

My beef is that the Apple Remote is useless for controlling volume. There is no settings app for the Apple Remote so that it controls the iTunes or current app's volume slider and not the system volume. However, the Remote app on iOS works fine at controlling a Mac's iTunes volume.

I have previously had this problem while converting a media center from Windows to Linux, however I had not expected it from my wife's brand new $2000 mac mini.

I asked about it at a local Apple re-seller while buying a mini displayport vga adapter, and the clerk told me it was "inconceivable!". Maybe he watched too much "Princess Bride" as a kid, but he wasn't very convincing, so I ended up here while looking it up.

I just installed Soundflower, and it works very well. It took a little fiddling, to make it work. As I remember, you have to set sound to go to Soundflower in system settings. Also I had to get it from code.google.com - the first dmg I downloaded would not install.

Thank you imwy2cool - this really is an issue, as more and more screens come out with only hdmi connections. This was driving me to distraction.

After using SoundFlower for a while I have noticed that it often crashes and tends to distort the sound quality rather badly. I also tried Boom, which enables the volume control in OSX, but dosn't actually do anything - regardless of controls, volume is either 0% or 100+%. I am still looking for the right solution.

Specifically, OS X outputs a PCM audio stream detailed here. The only exception to this is if you are passing through a Dolby Digital (AC3) or DTS audio stream from a media player in which case the PCM stream is superseded.

In the end, the only volume control you're going to get will be altering the audio data before it's sent over HDMI which can cause undesirable side effects. With VLC for instance yes you can alter the volume which in turn simply applies gain to the audio data, but eventually that will just lead to distortion and clipping. Using a 3rd party app to lower the volume simply compresses the waveform which in turn reduces the resolution of what's actually being played.

In conclusion, if you want the best possible sound do not use software to attempt to control the volume of a PCM audio stream. You want to apply volume changes after the data has been converted to a analog signal (what you actually can hear) which means using the TV or audio amplifier/receiver volume control.